The present disclosure relates generally to an adhesive that may be optimized for use in an embedded chip build up (ECBU) process. More particularly, present embodiments are directed to a photosensitive, thermoset adhesive that includes compositional features that facilitate successful build up of a module, establish final product reliability, and establish yield of an ECBU process.
Flip chip packaging may be defined as the direct electrical connection of face-down electronic components onto substrates, circuit boards, or carriers. For example, in a typical flip chip packaging procedure, the active side of a chip may be coupled to a substrate. This is in contrast to other techniques for chip packaging connection, such as wire bonding, wherein face-up chips are typically connected to each of various pads on the substrate using bond wire. The ECBU process may be categorized as a flip chip packaging procedure.
Flip chip packaging connections are generally considered to have numerous advantages over other techniques in performance, reliability, and versatility. However, there are also numerous challenges associated with traditional flip chip packaging. For example, the planarity of substrates and bump volume may be a limiting factor in successful and repeatable flip chip bonding of the type wherein each bump is required to contact a pad prior to reflow or thermo-compression bonding. Some of these challenges have been addressed by the ECBU process, wherein solder bump or wirebond interconnects may be eliminated by the use of a specialized material set and micro-via technology. The ECBU process generally includes attaching the active side of a chip to a substrate via adhesive and then drilling through the substrate and the adhesive to access bond pads on the active side of the die. It is now recognized that certain aspects of the adhesive may be substantially optimized to efficiently accommodate certain aspects of the ECBU process.